Ever since the early stages of the use of telephone systems, and particularly after party lines came into existence, a need has existed for remotely disconnecting a subscriber's telephone when he leaves it off of the hook. Hertofore when a subscriber has left his telephone off of the hook, it has been necessary for a repair man from the central office to travel to the subscriber's telephone and determine whether a malfunction existed, or whether the telephone was merely off of the hook. When one subscriber to a party line system leaves his telephone off of the hook, it is impossible for any of the other telephones on the party line to either dial out or have their telephone rung by an incoming call.
An object of the present invention therefore is the provision of a new and improved device to be installed remotely on a pair of communication lines for disconnecting the remote location when a low resistance condition exists across the lines at the remote location.
Another object of the invention is the provision of a new and improved telephone isolation device which can be operated from the central office to disconnect a subscriber's telephone from the system when the subscriber leaves his telephone off of the hook, and which will automatically restore the service when the subscriber puts the telephone back on the hook.
A still further object of the invention is the provision of a new and improved telephone isolation device which includes built-in resistances which can be monitored by the central office to aid in determining remotely whether or not the isolation device is operable.
Further objects and advantages of the invention will become apparent to those skilled in the art to which the invention relates from the following description of preferred embodiments described with reference to the accompanying drawing forming a part of this specification.